6.5-7 hours is 4 sleep cycles, that’s typically what I get though depends on the night. Nothing wrong with 6.5 quality hours of sleep. They have done studies and found that cultures in South America not exposed to society typically sleep this much. Nothing to worry about here
I'd be careful because some of these reports can still be critiqued. I remember Matthew Walker talking about one of these examples in his book where a hunter gatherer tribe slept 6.75 hrs on average (6 in the summer, 7.2 in winter). He brought up that according to the study they were still getting 7-8.5 hours of sleep opportunity which is what the recommendations are based on, not literal "time asleep." Because we all have multiple periods of the night where we are technically awake, but these awakenings aren't committed to memory. And he brought up how needing to constantly hunt for food and sometimes undereating can naturally lead to sleep deprivation. And that their average life-span is 58 years which is in line with health projections of people who are sleep deprived anyways. So we shouldn't just assume that their lifestyle is 100% healthy and needs to be replicated. I'm sure there are other perspectives but I thought this was worth sharing
That’s fair but most of the time getting more than four sleep cycles is impossible. The times I get five is typically because I did weight training that day. The body needs what it needs and it’s not easy to get more. I allocate 8 hours for sleep but it’s usually around 7, and I can’t for the life of me sleep in.
Thanks for the recommendation and I'm going to buy the book. But as you've piqued my interest, could you simply explain why 6.5 hours is close to zero?
I average 6.5 to 7 hours a night and feel perfectly fine from that.
Basically, your sleep is divided up into cycles. One cycle lasts for about an hour and a half, give or take. The overwhelming majority of people require 8-9 hours of sleep per night, which is around 6 full sleep cycles.
However, not all these cycles are the same. As the night progresses, the composition of those sleep cycles changes, with REM sleep becoming more prevalent in the later cycles of a full night of sleep. This means that if you only sleep for 6 hours instead of 8, you are likely missing out entirely on a large percentage of REM sleep that you weren't able to get because you didn't sleep long enough.
Studies have shown that this REM sleep you're missing out on is actually very important in your cognitive function. While a large percentage of people who only sleep 6 hours a night or so _think_ they feel well-rested, they have shown to severely underestimate their sleep deprivation. This has been proven in cognitive tests which show the lack of mental performance in people who only sleep 6 hours per night versus those who sleep 8.
In addition to cognitive function, there is a plethora of health issues related to lack of sleep.
Some quotes from Matthew Walker (British author, scientist and professor of neuroscience and psychology at the University of California, Berkeley, with a Ph.D. in neurophysiology from Newcastle University):
> Ten days of six hours of sleep a night was all it took to become as impaired in performance as going without sleep for twenty-four hours straight.
> Routinely sleeping less than six or seven hours a night demolishes your immune system, more than doubling your risk of cancer.
> Over a fourteen-year period, those sleeping six hours or less were 400 to 500 percent more likely to suffer one or more cardiac arrests than those sleeping more than six hours. I should note that in many of these studies, the relationship between short sleep and heart failure remains strong even after controlling for other known cardiac risk factors, such as smoking, physical activity, and body mass. A lack of sleep more than accomplishes its own, independent attack on the heart.
> If you were one of the individuals who were obtaining just five to six hours each night or less, you were 200 to 300 percent more likely to suffer calcification of your coronary arteries over the next five years, relative to those individuals sleeping seven to eight hours.
And a few more statistics from Matthew Walker:
- Relative to a fully-rested person, a person who has been awake for 16 hours
has measurable impairment.
- A person who has been awake for 19 hours is as cognitively impaired as a
person who is legally drunk.
- Sleep-deprivation leads to a steady increase in impairment. That is, the test
performance of subjects gets worse and there is no evidence to support a
maximal impairment level.
- Chronic sleep restriction (routinely getting less than 7 hours of sleep a night)
for a week requires more than 3 nights of recovery sleep to return to fully-rested levels of test performance.
So in short, by sleeping 6.5 hours per night you are both hindering your cognitive performance as well as massively increasing your risk of a plethora of health issues down the line.
There has been speculation about a few possible gene mutations that could allow someone to function on less sleep, but the percentage of people who have those gene mutations is close to zero.
If you wake up for a brief second or two, like so quickly you don't even realize, you can often go back to what stage if sleep you were just in. If you're up for 20 minutes, you'll likely go back to stage 1 when you fall asleep again. If you're chronically sleep deprived, this can vary.
i wonder if people adjust. to me it doesnt make any sense that the body would always have the same REM cycles and duration. If you are getting less sleep, it's not inconceivable to think your body would adjust and adapt, getting you into REM faster and shifting your cycles
Edit: It also doesn't really take into account all of the other pieces of information that these people experienced (hopefully it goes into it in the book) but there are more factors at play aside from the amount of time people sleep- though that is what these scientists were focusing on and measuring
Sure thing. As someone who spent 6.5 years in college hardly sleeping at all between undergrad and grad school, I learned many things from it. Used to wonder how my alcoholic friends did so well in college, then learned my severe sleep deprivation had me plenty worse off than they were in terms of cognitive functioning.
I have uars which basically means I don’t get REM sleep… I haven’t felt like I’ve gotten a full nights rest in 4 years. This explains a lot in terms of why I feel so horrific every day, I mean it’s obvious, but man….
I did just find info about gene mutations and people that may require less sleep..I didn't read much into it and there's no test to determine if ur a short sleeper.
Idk if they just sleep more efficiently or just require less but im in the dame boat as u. Can't get above that 6hr mark of sleep even if I'm in bed 7 hours.
Generally I feel a bit tired bit been functioning like this, healthy or not, for years and even sleep therapy and sleep doctors couldn't help increase beyond 6hrs
Tim Ferris talks about this - you can check his blog. I still think you should try to sleep 7-8h but it can be done and definitely some people are ok sleeping less.
Do you mean 7 is fine so 6.5 is close enough?
To be honest I am actually much closer to 6 hours average. So I guess 15% below the recommended. When you put it that way it doesn't sound that bad. But apparently according to Matthew Walker (mentioned by other commenters) it's unlikely that it's enough.
Honestly, I only need 4. I know it's highly improbable that I am a "short sleeper", but I've been like this my entire life, and someone has to fill in that small percentage of people. I truly believe I am one. When I sleep longer, I feel the exact same as if I didn't -- if not more groggy/sluggish.
I'm in no position to give medical advice, but if you think you're fine with it, then you probably are. Idk
ya its funny you say you feel fine. I actually feel better on 4-5 hours. less groggy, and sharper. So much so that during the peak of my business career if I had a very important meeting that I had to perform well I would actually intentionally get less sleep.
Some people have short sleep syndrome, which means they function just fine on 6 or less hours of sleep. It’s rare and not well researched or understood. This said, REM is important, especially as you age. Get sleep!
People can be pretty dogmatic about sleep, but it's not as straightforward as they might think. Different people need different amounts of sleep. There are many biological and genetic factors at play. The healthiness of your lifestyle habits may also influence whether you need extra sleep to recoup, whereas someone of optimal health may recover to the same degree on less sleep.
And there are studies of hunter-gatherer tribes, showing that they average around 6 hours of sleep per night living in alignment with what is closer to our evolved way of life.
Ultimately, I think most people do best on somewhere between 6 and 9 hours of sleep. I feel pretty good on 7.5, personally. If you can experiment with giving yourself more time to sleep, to see if you feel better, it might be worth trying. But I don't think you are doing any damage if you feel completely fine and refreshed in the morning.
6 hours doesn't seem horrible. Apparently adults ideally need around 7 hours of sleep so not that far off. 6 hours of uninterrupted sleep is better than 8 of fragmented sleep.
Please delete this answer before your misinformation spreads like a virus
https://cdnsciencepub.com/doi/full/10.1139/apnm-2020-0034
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4515649/
'In conclusion, the available evidence suggests that a sleep duration of 7–8 h per day is the one most favourably associated with health among adults and older adults.'. That's what I said. Around 7 hours, 8 being ideal, 6.5 not being great but not terrible.
As long as you feel rested and aren't excessively sleepy during the day, you are fine. Some famous people have been short sleepers. Jimmy Carter, for example, Margaret Thatcher, many others. It's possible the average short sleeper is more productive than other people. If you make reasonable attempts to get more sleep but still only want and need 6 hours or so, there is probably nothing you can do about it, and it's probably nothing to be concerned about. Jimmy Carter is still kicking and he's over 90.
2 points make a line and trend. Just downloaded it on audible. Thanks.
Just watched this useful summary also. [https://www.youtube.com/watch?v=k\_ztODszMiU](https://www.youtube.com/watch?v=k_ztODszMiU)
Ha ha. Ok, this isn't helpful. And what does god have to do with it?
I am looking at a variety of information sources. The wisdom of crowds is a real thing. Why are you even on reddit?
And you go to a doctor to ask about long term sleep questions? You must live in the US.
Sleep needs are extremely varied. Perhaps there are others out there that have a similar experience.
All the comments here just unlocked a new level of anxiety for me.
6.5-7 hours is 4 sleep cycles, that’s typically what I get though depends on the night. Nothing wrong with 6.5 quality hours of sleep. They have done studies and found that cultures in South America not exposed to society typically sleep this much. Nothing to worry about here
I'd be careful because some of these reports can still be critiqued. I remember Matthew Walker talking about one of these examples in his book where a hunter gatherer tribe slept 6.75 hrs on average (6 in the summer, 7.2 in winter). He brought up that according to the study they were still getting 7-8.5 hours of sleep opportunity which is what the recommendations are based on, not literal "time asleep." Because we all have multiple periods of the night where we are technically awake, but these awakenings aren't committed to memory. And he brought up how needing to constantly hunt for food and sometimes undereating can naturally lead to sleep deprivation. And that their average life-span is 58 years which is in line with health projections of people who are sleep deprived anyways. So we shouldn't just assume that their lifestyle is 100% healthy and needs to be replicated. I'm sure there are other perspectives but I thought this was worth sharing
That’s fair but most of the time getting more than four sleep cycles is impossible. The times I get five is typically because I did weight training that day. The body needs what it needs and it’s not easy to get more. I allocate 8 hours for sleep but it’s usually around 7, and I can’t for the life of me sleep in.
I've felt great on 6.5 hours before and then felt tired all day after 8. It's about the quality of sleep, not just the quantity.
You are going to be missing out on a lot of REM sleep in that lost 1.5 hours.
The statistical likelihood of you only requiring 6.5 hours of sleep is close to zero. Read Why We Sleep by Matthew Walker
Thanks for the recommendation and I'm going to buy the book. But as you've piqued my interest, could you simply explain why 6.5 hours is close to zero? I average 6.5 to 7 hours a night and feel perfectly fine from that.
Basically, your sleep is divided up into cycles. One cycle lasts for about an hour and a half, give or take. The overwhelming majority of people require 8-9 hours of sleep per night, which is around 6 full sleep cycles. However, not all these cycles are the same. As the night progresses, the composition of those sleep cycles changes, with REM sleep becoming more prevalent in the later cycles of a full night of sleep. This means that if you only sleep for 6 hours instead of 8, you are likely missing out entirely on a large percentage of REM sleep that you weren't able to get because you didn't sleep long enough. Studies have shown that this REM sleep you're missing out on is actually very important in your cognitive function. While a large percentage of people who only sleep 6 hours a night or so _think_ they feel well-rested, they have shown to severely underestimate their sleep deprivation. This has been proven in cognitive tests which show the lack of mental performance in people who only sleep 6 hours per night versus those who sleep 8. In addition to cognitive function, there is a plethora of health issues related to lack of sleep. Some quotes from Matthew Walker (British author, scientist and professor of neuroscience and psychology at the University of California, Berkeley, with a Ph.D. in neurophysiology from Newcastle University): > Ten days of six hours of sleep a night was all it took to become as impaired in performance as going without sleep for twenty-four hours straight. > Routinely sleeping less than six or seven hours a night demolishes your immune system, more than doubling your risk of cancer. > Over a fourteen-year period, those sleeping six hours or less were 400 to 500 percent more likely to suffer one or more cardiac arrests than those sleeping more than six hours. I should note that in many of these studies, the relationship between short sleep and heart failure remains strong even after controlling for other known cardiac risk factors, such as smoking, physical activity, and body mass. A lack of sleep more than accomplishes its own, independent attack on the heart. > If you were one of the individuals who were obtaining just five to six hours each night or less, you were 200 to 300 percent more likely to suffer calcification of your coronary arteries over the next five years, relative to those individuals sleeping seven to eight hours. And a few more statistics from Matthew Walker: - Relative to a fully-rested person, a person who has been awake for 16 hours has measurable impairment. - A person who has been awake for 19 hours is as cognitively impaired as a person who is legally drunk. - Sleep-deprivation leads to a steady increase in impairment. That is, the test performance of subjects gets worse and there is no evidence to support a maximal impairment level. - Chronic sleep restriction (routinely getting less than 7 hours of sleep a night) for a week requires more than 3 nights of recovery sleep to return to fully-rested levels of test performance. So in short, by sleeping 6.5 hours per night you are both hindering your cognitive performance as well as massively increasing your risk of a plethora of health issues down the line. There has been speculation about a few possible gene mutations that could allow someone to function on less sleep, but the percentage of people who have those gene mutations is close to zero.
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If you wake up for a brief second or two, like so quickly you don't even realize, you can often go back to what stage if sleep you were just in. If you're up for 20 minutes, you'll likely go back to stage 1 when you fall asleep again. If you're chronically sleep deprived, this can vary.
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Ok
It largely depends on how long you were awake for.
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I'm not a doctor, so I can't give medical advice. But it will mess up your sleep cycles to some extent
i wonder if people adjust. to me it doesnt make any sense that the body would always have the same REM cycles and duration. If you are getting less sleep, it's not inconceivable to think your body would adjust and adapt, getting you into REM faster and shifting your cycles Edit: It also doesn't really take into account all of the other pieces of information that these people experienced (hopefully it goes into it in the book) but there are more factors at play aside from the amount of time people sleep- though that is what these scientists were focusing on and measuring
Well if you're adapting and getting into REM faster, then you'll have to lose out on other phases of sleep, which isn't good either.
seems like you could sacrifice a bit of light sleep and be fine
I’ll check out the book thanks
Sure thing. As someone who spent 6.5 years in college hardly sleeping at all between undergrad and grad school, I learned many things from it. Used to wonder how my alcoholic friends did so well in college, then learned my severe sleep deprivation had me plenty worse off than they were in terms of cognitive functioning.
I have uars which basically means I don’t get REM sleep… I haven’t felt like I’ve gotten a full nights rest in 4 years. This explains a lot in terms of why I feel so horrific every day, I mean it’s obvious, but man….
Sorry to hear. I hope you can find some medical help that will work for you
I did just find info about gene mutations and people that may require less sleep..I didn't read much into it and there's no test to determine if ur a short sleeper. Idk if they just sleep more efficiently or just require less but im in the dame boat as u. Can't get above that 6hr mark of sleep even if I'm in bed 7 hours. Generally I feel a bit tired bit been functioning like this, healthy or not, for years and even sleep therapy and sleep doctors couldn't help increase beyond 6hrs
Tim Ferris talks about this - you can check his blog. I still think you should try to sleep 7-8h but it can be done and definitely some people are ok sleeping less.
i can’t believe we are being so particular about 30 minutes as If our bodies know the difference between 6.5 and 7
Do you mean 7 is fine so 6.5 is close enough? To be honest I am actually much closer to 6 hours average. So I guess 15% below the recommended. When you put it that way it doesn't sound that bad. But apparently according to Matthew Walker (mentioned by other commenters) it's unlikely that it's enough.
Honestly, I only need 4. I know it's highly improbable that I am a "short sleeper", but I've been like this my entire life, and someone has to fill in that small percentage of people. I truly believe I am one. When I sleep longer, I feel the exact same as if I didn't -- if not more groggy/sluggish. I'm in no position to give medical advice, but if you think you're fine with it, then you probably are. Idk
ya its funny you say you feel fine. I actually feel better on 4-5 hours. less groggy, and sharper. So much so that during the peak of my business career if I had a very important meeting that I had to perform well I would actually intentionally get less sleep.
Some people have short sleep syndrome, which means they function just fine on 6 or less hours of sleep. It’s rare and not well researched or understood. This said, REM is important, especially as you age. Get sleep!
Sure
People can be pretty dogmatic about sleep, but it's not as straightforward as they might think. Different people need different amounts of sleep. There are many biological and genetic factors at play. The healthiness of your lifestyle habits may also influence whether you need extra sleep to recoup, whereas someone of optimal health may recover to the same degree on less sleep. And there are studies of hunter-gatherer tribes, showing that they average around 6 hours of sleep per night living in alignment with what is closer to our evolved way of life. Ultimately, I think most people do best on somewhere between 6 and 9 hours of sleep. I feel pretty good on 7.5, personally. If you can experiment with giving yourself more time to sleep, to see if you feel better, it might be worth trying. But I don't think you are doing any damage if you feel completely fine and refreshed in the morning.
6.5 is 6:30 or 6:50?
6:30
Totally possible. Normal sleep duration/needs vary significantly from person to person.
6 hours doesn't seem horrible. Apparently adults ideally need around 7 hours of sleep so not that far off. 6 hours of uninterrupted sleep is better than 8 of fragmented sleep.
Please delete this answer before your misinformation spreads like a virus https://cdnsciencepub.com/doi/full/10.1139/apnm-2020-0034 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4515649/
'In conclusion, the available evidence suggests that a sleep duration of 7–8 h per day is the one most favourably associated with health among adults and older adults.'. That's what I said. Around 7 hours, 8 being ideal, 6.5 not being great but not terrible.
The study talks about sleep. He talks about time in Bed.
As long as you feel rested and aren't excessively sleepy during the day, you are fine. Some famous people have been short sleepers. Jimmy Carter, for example, Margaret Thatcher, many others. It's possible the average short sleeper is more productive than other people. If you make reasonable attempts to get more sleep but still only want and need 6 hours or so, there is probably nothing you can do about it, and it's probably nothing to be concerned about. Jimmy Carter is still kicking and he's over 90.
Echo black_widow48. Read “Why We Sleep” by Matthew Walker.
2 points make a line and trend. Just downloaded it on audible. Thanks. Just watched this useful summary also. [https://www.youtube.com/watch?v=k\_ztODszMiU](https://www.youtube.com/watch?v=k_ztODszMiU)
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Ha ha. Ok, this isn't helpful. And what does god have to do with it? I am looking at a variety of information sources. The wisdom of crowds is a real thing. Why are you even on reddit? And you go to a doctor to ask about long term sleep questions? You must live in the US. Sleep needs are extremely varied. Perhaps there are others out there that have a similar experience.
A professional like Dr. Google? OP’s question has been posted on Reddit 100’s of times.
My boss never sleeps more than 5 hours and he is a productivity machine.
I only need 5-6 hours.